Method of treating tacky strand material

ABSTRACT

STRAND MATERIAL OF TACKY DISPOSITION IS TREATED BY APPLICATION OF A ROOM TEMPERATURE SOLIDIFIED LUBRICANT MATERIAL UNDER CONDITIONS AS TO YIELD A SOLID, FILM-LIKE LAYER OF THE MATERIAL DEPOSITED ON THE STRAND SUFFICIENTLY COEXTENSIVE AS TO AVOID SURFACE-TO-SURFACE CONTACT WHEREBY THE CONTINUOUS LENGTH OF MATERIAL WOUND ON SPOOLS OR THE LIKE MAY BE WITHDRAWN THEREFROM RAPIDLY.

Jan. 1,1974 J E ETAL 3,782,996

METHOD OF TREATING TACKY STRAND MATERIAL Filed April 16, 1968 2 Sheets-Sheet l FIG. 5

FIG.

INVENTORS dramas QBEkUE BYROBERT SSQHAEFER Ame UEVS Jan. 1, 1974 J, c BELUE ET AL 3,782,996

METHOD or TREATING 'IACKY STRAND MA'lERlAL Filed April 16, 1968 2 Sheets-Sheet 2 F I G. 2 INVENTORS JAM ES C. BELUE BYR BERT SSwAEFER ATIERMEUS United States Patent '0 3,782,996 Patented Jan. 1, 1974 fine:

US. Cl. 117-45 6 Claims ABSTRACT OF THE DISCLOSURE Strand material of tacky disposition is treated by application of a room temperature solidified lubricant material under conditions as to yield a solid, film-like layer of the material deposited on the strand sufliciently coextensive as to avoid surface-to-surface contact whereby the continuous length of material wound on spools or the like may be withdrawn therefrom rapidly.

The present invention relates to a treatment directed to avoid problems in the handling and processing of bodies, particularly continuous lengths formed of various materials and compositions, which are for one reason or another of tacky disposition.

More particularly, the present invention relates to a continuous length of a multifilament strand which carries exteriorly and/or interiorly a vulcanizable elastomeric impregnant; which, by reason of its being vulcanizable, is quite tacky, e.g., sticky. When such a product is wound onto a given spool to form a package, repeated courses or winds tend to adhere to adjacent courses or winds whereby further processing, as by unwinding, rewinding, plying, plaiting, twisting, etc., is only accomplished with difficulty and at very low speed. It has also been found that the tacky nature or disposition of the impregnant on the wound strands leads to breakdowns and stoppages in later processing of the strand due to this phenomena.

In the past, various dry, powdery materials have been applied to the strand or yarn material in one way or another in an effort to overcome these problems. Unfortunately, these efforts have fallen short of accomplishing the desiredresults and, in some cases, without overcoming the problems at all. In the first place, the application of the powdery materials represents an inplant housekeeping problem since these known materials are so finely divided, e.g., fluffy, that they become spread all over the plant area where used and even remote areas where further processing takes place, e.g., when the strand is unreeled, releasing the fiuffy powder. Furthermore, these materials such as soap stone, talc (a magnesium silicate) etc., tend to become overly used, leading to accumulations of powder material at spaced intervals along the continuous strand. Conversely, areas are found that are not dusted with the material and therefore the tackiness problem is not solved at all but may continue to plague the use of the particular strand textile material further down the line.

The variation in the accumulation of the dusting material on the strand also leads to somewhat erratic results in the speed of processing machinery downstream. Furthermore, the variations in the amount of material on the continuous strand may and frequently does interfere with the employment of this continuous strand material in the ultimate product into which it is incorporated as an integral part.

It is also found that the employment of these dusting powders, such as talc, results in a product which is frequently unacceptable to a purchaser. Thus, the continuous strand material, bearing an elastomeric impregnant, is not always continuously processed. to an ultimate product in a given plant facility. Rather, a given textile manufacturer may sell to a customer a supply spool containing a measured amount of the continuous strand bearing an elastomeric impregnant component. If the package of strand material must contain dust and/ or a variant amount of dust, it will be appreciated that these factors can present a considerable hurdle to customer satisfaction.

With the foregoing in mind, it is an object of the present invention to provide an improved method of treatment for continuous strand material of tacky disposition; which method avoids the problems enumerated hereinabove.

It is a particular object of the present invention to provide a method of treatment which is relatively simple to accomplish, yet very expeditiously eliminates the problem of adhesion, housekeeping, poor release and consequent slow unwinding, twisting and plying.

It is a particular object of the present invention to provide a method which completely obviates the problems of repeated winds of strand material in a package adhering to itself and which at the same time does not materially alter the appearance of the package in the eyes of the consumer.

It is still another object of the present invention to provide a method of treatment which provides an extremely thin, film-like layer which is continuous along the length of the tacky strand material whereby release in unwinding is substantially uniformly instantaneous, permitting utilization of high speed machinery in the further processing of the product so treated.

It is a particular object of the present invention to provide such a method which completely eliminates the housekeeping problems normally associated with the employment of the powdery lubricant materials.

It is a principal object of the present invention to provide a package construction composed of wound strand material including a tacky elastomeric component and, in addition, a continuous layer of a room temperature solidified lubricant material located on said strand in such fashion as to be substantially coextensive with the otherwise physical contact area of the strand in its wound disposition upon the core or spool member.

The foregoing, as well as other objects of the present invention, will become apparent to those skilled in the art from the following detailed description taken in conjunction with the annexed sheets of drawings on which there is presented, for purposes of illustration only, a pri* mary embodiment of the present invention.

FIG. 1 is a schematic, side elevation view illustrating the practice of the technique of the present invention in a particular impregnation process;

FIG. 2 is a side elevation view of the particular apparatus (shown greatly enlarged) employed in treating strand material in accordance with the technique of the present invention;

FIG. 3 is a schematic plan view illustrating a package composed of a core spool having continuously wound thereon a continuous strand material including an elastomeric impregnant;

FIG. 4 is an enlarged view of one portion of the package of FIG. 3 but with the strand material cut away to illustrate schematically the surface-to-surface relationship of the repeated winds of strand material; and

FIG. 5 is a schematic sectional view of one of the strand segments of FIG. 4 illustrating the location and character of the lubricant material in accordance with the present invention.

The nature of the present invention will become more apparent from the following description wherein reference will be had to the impregnation line shown in FIG. 1; it being appreciated that this is set forth only as a typical facility involving the processing of a continuous strand-like material having inherent surface tack which otherwise presents a serious problem for later processing of the material.

In FIG. 1, the reference numeral 11 identifies a creel area containing a plurality of rotatable spools, each containing a strand component of a plurality of continuous glass filaments. The strands are desirably combined with like strands to form a lesser plurality of yarns or cords as at 13. The composite yarns are passed in horizontal spaced parallel array through an impregnation station 15 and thence through a single or double stage oven to dry. The impregnation station involves the application to the strand or cord of a liquid frequently including an elastomeric component. In the oven, the impregnated yarn is dried and also partially cured. From the oven, the strands are directed up over overhead guides 70 and to the winder area, generally designated 18, wherein a plurality of winder units collect the impregnated yarns onto paperboard spools. When a measured amount of yarn is wound on a given spool, the winder is stopped and the package, e.g., the spool containing the continuous supply of impregnated cord, is removed for subsequent processing or for sale to a user who himself further processes the yarn; for example, combining the yarn with other yarns, Weaving it, plying or the like and then finally incorporating the yarn into an ultimate product.

In accordance with the present invention, as the yarn emerges from the oven 16, it passes through a station this station being composed of an apparatus illustrated in more detail in FIG. 2. The apparatus 20 consists of support legs 2122, a horizontal cross platform 23 spanning the legs 21-22 and an upper cradle assembly 24 supported by the legs 21-22. The cradle encloses a metal trough 25 having downwardly converging side walls 26 and 27, spanned by a bottom wall 28. End walls 29, only the closest of which can be seen (the other being hidden from view), complete the open topped trough. The trough is preferably formed of stainless steel. The diverging walls, the bottom wall and the end walls of the trough all have releasably affixed to the outer surfaces thereof, in flush abutting relationship, electrical resistance heating elements identified by the reference numeral 30. The reference numeral 30a identifies a securement bracket for holding the elements 30 as just described.

The upper cradle includes a lateral wing plate 31 on the left and a similar wing plate 33 on the right, both extending outwardly and horizontally. A plurality of sideby-side guide eyes 34 are mounted on the plate 31. A support block 36 at each end of the wing plate 33 bears a journal support 38 in which is rotatedly mounted the ends of a freely rotatable roller 40. Within the trough, there is located in suitably mounted position a linear roller 43 carried by a shaft 45. The shaft 45 bears coaxially mounted at one end a sheave 47 connected by V-belt 49 to a like sheave 50 mounted on shaft 52 of an electric motor M which is connected to a suitable source of power to rotate the components and particularly the roller 43. The eyelet 34 and the roller 40 on opposite sides of the horizontal roller 43 are so adjusted vertically that the strands S, moving in the direction indicated by the arrow 60, pass through the eyelet 34, thence in a very slightly up wardly inclined path over the roller 43, thence in a very slightly downwardly inclined path under the roller 40 and thence in a sharply upwardly inclined direction over the suitable friction-free guideways 70 (see FIG. 1). The path of the strands through this station is thus not absolutely horizontal but rather describes a slightly upward path before it hits the roller 43 and a slightly downward path after it passes the roller 43.

Zinc stearate in the molten state is present in the trough 25 and is maintained in the molten state by heat developed by electrical resistance elements such as Calrod elements. The liquid level of the molten zinc stearate is identified by the reference numeral 72. As can be seen, the roller is partially submerged in the molten zinc stearate. The rotation of the roller 43 may be in either direction, but preferred practice in accordance with the invention dictates a direction of rotation in which the periphery of the top portion of the roller is moving in the same direction as the strand S as described herein'before. The molten zinc stearate is maintained at just above the melting point of 266 F. (133 C.) where the viscosity may be likened to a light syrup or a medium thick cream. Under these conditions, it will be appreciated that the roller surface picks up a thin film measuring about 0.0050.020". The multifilament strand moves horizontally at a speed of 200400 feet per minute while the peripheral speed of roller is about .01 times that speed. For a three and one-half (3 /2) inch diameter roller, the corresponding revolutions per minute is about 3.0. Considering the relative speed and the very slight contact of the strand with the roller bearing the thin film of this molten zinc stearate, we are able to provide for transfer to the moving strand of a very thin film of the zinc stearate which solidifies almost instantaneously with the termination of the kiss coating contact of the strand with the roller.

A package composed of a paperboard spool 81 and wound thereabout an endless length of strand material 82 treated in accordance with this invention is illustrated in FIG. 3. As can be seen, the package is a square package in which the repeated winds of the strand 82 as shown in FIG. 4 are in a fairly regular ordered relationship with each other. In accordance with the present invention, the strand bears on its underside 83 the solid film-like layer of zinc stearate which extends continuously on the underside of the strand and for approximately half the circumference of the strand reaching from the point identified 'by the reference numeral 84 to the point identified by the reference numeral 85. This film and the extent thereof, as reference again to FIG. 4 reveals, serves to insulate against mutual contact of the tacky surfaces of the strands 82. It will be appreciated that control of the strand speed, the direction of rotation and speed of the pickup roller and the viscosity of the molten zinc stearate can be adjusted to modify the extent of coverage and, as well, the thickness of the film of the molten zinc stearate 83. Generally, the film thickness on the strand need not exceed about 0.001 inch.

For purpose of illustration, in both FIGS. 4 and 5, the thickness of the film-like layer 83 has been considerably exaggerated in comparison to the size of the impregnated multi-filament strand 82. As a matter of fact, examination of a package, and more particularly the strand thereon, does not readily reveal the presence of the film-like layer of the room temperature solidified zinc stearate. The briefness of the contact with the roller, coupled with the temperature of the molten zinc stearate and the room temperature of the surrounding atmosphere, results in the very rapid solidification and almost instantaneous solidification of the zinc stearate once it passes out of contact with the pickup roller 43 and beneath the idler roller 40.

From the foregoing, it can be readily appreciated that the housekeeping problems attendant the use of the normally flutfy soap stone and talc powders is completely avoided since the molten yet room temperature solidifiable zinc stearate is maintained solely within the open topped trough and the amounts transferred to the strand are so slight that there is no subsequent flaking off of white powder. As a matter of fact, while zinc stearate in its normal solid form, e.g., small chunks or granules, is normally white to wax white in color, as borne as a continuous layer on the underside of the strand, as described above, the film-like deposition of zinc stearate appears essentially clear and transparent.

Experience over a period of time has demonstrated that the package, such as the package 82 in FIG. 3, wherein the strand wound thereon has been treated in accordance with the present invention, even after storage for some time is capable of releasing the strand thereon very readily and rapidly so that high speed plying, winding and twisting equipment can be used with essentially no difiiculty whatsoever from the standpoint of release of the strand. It is further observed that the film-like character of the zinc stearate, achieved by its rapid cooling to room temperature from the applied molten state, is quite permanent, remaining secured to the strand with no observable rub off or static flake off as might otherwise be noticed in any accumulation thereof on or about the machinery utilized subsequently in processing the strand material.

Zinc stearate is a preferred metal soap material for treating the tacky strand of material in accordance with the present invention. Zinc stearate has a melting point of 266 F. (133 C.) which is very readily accomplished in the trough electrically heated as illustrated in FIG. 2. Furthermore, it exhibits the desirable property of quick drying to a securely attached, solidified film-like layer on the coated strand. Additionally, considering a multifilament strand impregnated with a vulcanizable elastomer, it will be appreciated that zinc stearate is readily compatible with an ultimate vulcanization reaction as the impregnated strand will be subjected to when embedded in a rubber product. Reference to any standard reference work reveals a number of other metallic soap materials; the most common and preponderant amount of which are salts of long chain fatty acids. One such material is magnesium myristate having a melting point of 268 F. (131.6" C.) Sodium palmitate, magnesium stearate, potassium myristate and potassium palmitate are other metal salts of the faty acids ranging from 12 to 18 carbon atoms which are chemically related to zinc stearate and which have melting points of the same order of magnitude. By reason of their relative inactivity, the magnesium and zinc salts of these fatty acids are more preferred than the more active alkali and alkaline earth metal salts, considering that these metal soaps should be relatively stable for extended periods of time in the molten state without undergoing regression, change or decomposition. Otherwise, of course, the impregnation line would have to be shut down for recharging with fresh material in addition to melting time. It is also preferred that the anion of the salt should be selected from the saturated acids since they are more stable at the elevated temperature as compared to the unsaturated acid moieties. This is not to say, of course, that certain of the unsaturated acids are not suitable, particularly where the amount of unsaturation is very small, for example, as in the case of oleic acid. As a matter of fact, the commercial products, e.g., metal soaps, usually contain some free or loosely combined fatty acids as Well as hydrates and basic .soaps other than those indicated by the name of the particular soap marketed.

It will be appreciated that the molten metal soap can be applied over the entire surface area of the strand; and

in the processing and treatment of certain continuous strand materials having inherent surface tack, such technique may be utilized and considered within the broad scope of this invention. In the particular application in which the present'treatment of this invention was described, it is preferred that the molten material be, in effect, applied selectively to the underside of the strand by the described kiss coating technique. This avoids the possible attendant necessity of wiping excess lubricant from the strand. Furthermore, a completely coated or encapsulated strand is not as desirable in may respects, e.g., as to handling properties, as a strand bearing a layer which is not complete, considered peripherally of the strand, but is complete or continuous considered linearly of the strand.

Liquid preparations of the metal salts discussed hereinabove are available and are included within the broader aspects of the present invention. However, the use of the molten form of the metal salts, particularly the fatty acid salts of the metals: calcium, magnesium, sodium, potassium, zinc and mixtures thereof, is most preferred since the uniformity of application, quickness of drying and release characteristics are more pronounced with these materials.

In the interest of clarity, simplicity and conciseness, the invention has been principally defined in terms of the particularly commercial application wherein it has been proved utilitarian; namely, in the treatment of elastomer impregnated multifilament yarns. It is envisioned, however, that the invention is of a broader application. Thus, the described treatment is believed applicable in the continuous processing of linear bodies formed, for example, in extruding rubber in the unvulcanized state or subsequent to the application of a rubber coating to wire and prior to cure. Additionally, any number of other products may well be improved by a coating of room temperature solidified metalsoaps applied while in the molten state.

The particular treatment as herein described has proven extremely satisfactory in connection with a rubber impregnated strand or yarn construction composed of a plurality of continuous glass filaments.

Variations in technique and materials will suggest themselves to those skilled in the art from the foregoing description and such obvious variations are intended to be included unless clearly violative of the language of the appended claims.

We claim:

1. In the method of impregnating a multifilament strand with an elastomeric material in order to improve its ultimate compatibility and adhesion with a vulcanized elastomeric product wherein said strand is continuously unreeled, coated with an elastomeric impregnant, heated to partially v-ulcanize said elastomeric material and dry said impregnant to partially reduce the inherent tack of said elastomeric material and then collected on a rotating spool; the improvement wherein, after heating and before collection, said strand is coated with a solid lubricant while said lubricant is in the liquid state, said lubricant being capable of solidifying substantially immediately after application to said strand to form a continuous filmlike layer of said lubricant material.

2. The method as claimed in claim 1, wherein said liquid lubricant is applied to just one side of said strand.

3. The method as claimed in claim 2, wherein said lubricant material is a metal salt of a fatty acid, said metal being selected from the group consisting of calcium, magnesium, sodium, potassium, zinc and mixtures thereof and mixtures of said salts.

4. The method as claimed in claim 3, wherein said metal salt is applied while molten.

5. The method as claimed in claim 4, wherein said metal is zinc.

6. The method as claimed in claim 5, wherein said salt is a stearate.

(References on following page) 7 8 References Cited 3,368,917 2/1968 Belcher et a1. 117--139.5 X 3,383,242 5/1968 Macura et a1. 117-4395 X UNITED STATES PATENTS 3,421,926 1/1969 Davies et a1 11766 7/1926 Hoffman et a1.

l17-Anti-stick digest FOREIGN PATENTS 11/ 1935 Beach et a1, 5 708,278 5/1954 Great Britain 117-80 117-Hot melt digest 1940 Murray 7 melt digest ALFRED L. LEAVITT, Prlmary Examiner 3/ 1941 Cornwall 117Anti-stick digest T. E. BOKAN, Assistant Examiner 3/1962 Eilerman 117-1395 X 10 6/1964 'Nakane 117 139.5 X 2/1965 MacHenry et a1. 11766 117--66, 72, 75, 76 R, 76 T, 77, 79, 80, 87, 88, 89, 90 

